There has conventionally been provided a washing machine including dampers which support a water tub mounted in an outer casing between the outer casing and the water tub thereby to absorb vibration of a rotating tub (an inner tub) and accordingly, vibration of the water tub. This type of damper employs as an operating fluid a magnetic viscous fluid (MR fluid) changing its viscosity according to the intensity of magnetic field.
The damper includes a cylindrical member (a cylinder) enclosing the magnetic viscous fluid and electromagnets disposed around the cylindrical member. The viscosity characteristics of the magnetic viscous fluid are changed by controlling electric current applied to the electromagnets by a controller. The water tub is provided with a sensor serving as a vibration detection unit. The current to be applied to the electromagnets is controlled on the basis of a detection signal generated by the sensor, so that a damping force is changed.
In the above-described washing machine, however, the control of the damper is not started unless an increase in vibration is detected by the sensor. More specifically, the control of the damper premises the detection of vibration by the sensor and is thus an ex-post operation. Accordingly, an effect of suppressing vibration and noise is insufficient and in particular, a large vibration is produced during a dehydrating operation.